A theoretical study on the alkene insertion step in Rh-Yanphos catalyzed hydroformylation

This paper studied the mechanism of the alkene insertion elementary step in the asymmetric hydroformylation (AHF) catalyzed by RhH(CO)(2)[(R,S)-Yanphos] using four alkene substrates (CH2=CH-Ph, CH2=CH-Ph-(p)-Me, CH2=CH-C(=O)OCH3 and CH2=CH-OC(=O)-Ph, abbreviated as A1-A4). Interestingly, the equatorial vertical coordination mode (A mode) with respect to the Rh center was found for A1 and A2 but not for A3 and A4, although the equatorial in-plane coordination mode (E mode) was found for A1-A4. The relative energy of the E mode of the eta(2)-intermediates is lower than that of the A mode. In the alkene insertion step, Path 1 is more favorable than Path 2 for this system. As for A1 and A2, there could be a transformation between 2(eq) and 2(ax) (C) 2013 Ming Lei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.